1 files changed, 20 insertions, 0 deletions
diff --git a/tests/testdata/run/015_duplicate_parallel_import.js b/tests/testdata/run/015_duplicate_parallel_import.js
new file mode 100644
index 000000000..2fbe2c732
--- /dev/null
+++ b/tests/testdata/run/015_duplicate_parallel_import.js
@@ -0,0 +1,20 @@
+// Importing the same module in parallel, the module should only be
+// instantiated once.
+
+const promises = new Array(100)
+  .fill(null)
+  .map(() => import("../subdir/mod1.ts"));
+
+Promise.all(promises).then((imports) => {
+  const mod = imports.reduce((first, cur) => {
+    if (typeof first !== "object") {
+      throw new Error("Expected an object.");
+    }
+    if (first !== cur) {
+      throw new Error("More than one instance of the same module.");
+    }
+    return first;
+  });
+
+  mod.printHello3();
+});